The present invention relates to memory devices, and, more particularly, to a three-dimensional (3D) memory device and its driving method.
With the advance of semiconductor fabricating techniques, high-density memories have been increasingly in demand. Various approaches have been proposed to satisfy such demands. One of the approaches is a memory device with a 3D array structure (hereinafter, referred to as a 3D memory device).
The 3D memory device typically includes memory cell arrays which are formed in multiple semiconductor material layers. The semiconductor material layers typically include a well-known silicon substrate and substrates sequentially stacked on the silicon substrate. The stacked substrates, for example, are typically formed by the use of epitaxial process techniques.